mineral specimens
rare minerals
mineral dealer
systematic minerals
Black Hills minerals
fine minerals
mineral dealer
Dana minerals
IMA minerals
mineral collections
rock and minerals
gem crystal
0 item @ $0.00  

Nepheline Syenite var. Foyaite

#PD44480

Nepheline Syenite var. Foyaite

#PD44480
Availability
Sold
Size
16 x 12 x 1 cm - Cabinet 
Formula
KNa3(AlSiO4)4 (RRUFF)
Locality
Picota Mountain, Monchique, Algarve, Portugal

This is more of a petrological specimen than a mineral specimen. It is a large slab of what is known as "foyaite", which is a nepheline syenite (quartz poor) with 1-3cm phenocrysts of orthoclase.

Nepheline

Formula
KNa3(AlSiO4)4 
Crystal System
Hexagonal 
Crystal Habit
Massive - Granular, Prismatic 
Cleavage
Poor, None, None 
Luster
Vitreous - Greasy 
Color
white, gray, brown, brownish gray, reddish white 
Streak
white 
Class
Hexagonal - Pyramidal 
Fracture
Sub Conchoidal 
Hardness

Data courtesy of Webmineral.

Collection
Phillips Collection
Mineralpedia
View Nepheline
On Dakota Matrix
Previously Sold Nepheline
On Dakota Matrix
Other Available Nepheline
WebMineral
View Nepheline
Mindat
View Nepheline

All photos by Dakota Matrix and are Copyrighted © and may not be used without permission. Copyright © 2021 - Dakota Matrix Minerals, Inc. Privacy | Terms & Conditions | Site Map